In a semiconductor device manufacturing process, the following method has heretofore been used to analyze a sample. An electron beam is applied to the surface of the sample. Secondary electrons, reflected electrons, and others that are generated from the sample surface accordingly are detected, and signals are output. The obtained signals are then processed to analyze the material, structure, shape, and potential distribution of the sample. As an apparatus that enables such an analysis, for example, a scanning electron microscope (hereinafter briefly referred to as an “SEM”) is used. The SEM generates a two-dimensional contrast image from the signals obtained by detecting the secondary electrons and reflected electrons from the sample.
In the conventional SEM, the enhancement of the resolution of the two-dimensional contrast image has been regarded as important. Accordingly, techniques have been developed to collect electrons generated from a sample as efficiently as possible to improve the S/N ratio.
This has caused the following problem. Electrons having different energy and different output vectors are collected, and secondary electrons that are spread in regard to energy come into one detector due to an interaction with the sample surface. As a result, information regarding the spread of the energy received from the sample surface is lost.